1. Field of Invention
The inventive concepts disclosed and claimed herein relate generally to digital image processing and, more particularly, but not by way of limitation, to finding and selecting points of interest on an edge of interest in a digital image.
2. Brief Description of Related Art
In the remote sensing/aerial imaging industry, imagery is used to capture views of a geographic area to be able to measure objects and structures within the images as well as to be able to determine geographic locations of points within the image. Such imagery is described in, for example, U.S. Patent Application Publication No. 2008/0231700. Photogrammetry is the science of making measurements of and between objects depicted within photographs, especially aerial photographs. A person, or User, may interact with the image to select Points of Interest that may be used to perform other functions such as: determine distance between two points; determine the area outlined by a set of points; determine the volume of a 3-dimensional shape, or other functions. Usually, the greatest error induced into the calculation of the function is the human error introduced by the User selecting the Points of Interest. For example, if a measurement from a building to the edge of a curb is desired and the User selects a point that is close to the edge of the building, but not the actual edge of the building, then the measurement will differ from the actual measurement by the distance the User selected away from the building. In the projected image, several pixels could significantly impair the accuracy of the measurement. Additionally, when multiple Users perform the same measurement, their results can differ significantly.
In light of the foregoing, there is a need for a system and process for allowing a User to select Points of Interest based on the edge elements that exist in a geo-referenced image, wherein the Points of Interest are determined without the error caused by human determination of the position of the edge of an element in an image.